THREE missing sisters have been found dead days after they were reported missing while visiting their dad.

Authorities are being accused of “failing” the sisters by not issuing an Amber Alert for them as cops launch a manhunt for their father, who is charged with kidnapping and killing them.

Paityn, 9, Evelyn, 8, and Olivia Decker, 5, were found dead on Monday night after cops swarmed Rock Island Campground, about an hour outside of Wenatchee, Washington.

Cops are now searching for Travis Decker, 32, who the girls were last seen with on what was supposed to be a three-hour custody visit on Friday.

Decker, who cops say is homeless, didn’t drop his daughters off at the end of the visit, prompting their mom to report them missing that night.

Washington State Patrol then issued an endangered missing persons alert for the siblings this weekend after Decker was seen leaving Wenatchee with the girls.

Cops decided not to send out an Amber Alert, designed to warn of child abductions, because they thought it was a custody issue.

“AMBER alerts involve more imminency, like we know something will happen, versus what we were dealing with over the weekend was more of an overdue child scenario,” Wenatchee Police Sgt. Joe Eaton told NCWLIFE.

Now, members of the public are lashing out at police for not doing more to alert people to the unfolding situation.

“This isn’t just heartbreaking, it’s infuriating,” one Facebook user commented on WPD’s Facebook post.

“These girls are gone because the system FAILED them. The police didn’t take it seriously, and the court system let them down too.

“There was a predator out there and instead of protecting our community, you stayed silent. No alerts, no warnings nothing.”

Another wrote, “How come an amber alert was not issued until it made national news? You failed this mother and her kids.

“The amber alert should have been issued the day he didn’t come back and no contact could be made.”

Cops warned members of the public not to approach Decker, a veteran who they believe is mentally unstable.

He was living out of his truck, which was found abandoned on the campground with the girls’ bodies.

It’s unclear how the three girls died.

His ex-wife, the girls’ mom, previously shared there were never any problems with their daughters visiting Decker in the past.

“Travis has really struggled since he left the military and his mental health can be hard sometimes,” Whitney Decker told CBS affiliate KIRO.

“I think this is an effect of that, and I don’t personally think that he’s dangerous.

She said at the time, “I think that he is impulsive and he loves his children very much.”

Wenatchee Police Department said in a press release on Saturday that Decker is homeless and lives in his truck, in hotels, or at campgrounds in the area.

“The visitation was part of a parenting plan, but he has since gone outside the parameters of it which is not normal and cause for the alarm,” cops said at the time.

A GoFundMe to support Whitney has raised $50,000 of its $100,000 goal.

“These girls were true light in this world and and it is a darker place without them,” the fundraiser’s organizer wrote.

“I will miss seeing their sweet little faces.”